I act out of knowing how the left (hard ffs) is treated when the right have the upper hand in the party.
The left, me included were delighted when Blair won, he was voted in by all parts of the party as he promised the earth, but took the left for granted as if we would always be there and we ended up being just voting fodder for him to do as he wished and he didn't deliver on his promises to the left. During that time the left stayed broadly loyal, a few minor exceptions but broadly loyal as he was elected leader and PM. Brown and Ed Miliband were also backed by the left and again the left stayed loyal and upheld party unity. The left stayed loyal even when twats like Reeves voted for welfare cuts, we didn't moan or stage a coup, we were unified behind the leadership.
Then Corbyn won again voted in by a majority of party members, but almost straight away the PLP plotted against the left and organised a coup. The right of the Labour party are the ones who are disloyal, it was them who plotted and undermined the Labour party and after all those years of us on the left backing leaders who came from the right of the party it stuck in the craw. We did our bit for party loyalty but got zero loyalty in return from the right.
So no I don't act as though the Labour party belongs to the left, I do think it should be a Socialist party and not a socially liberal party but I have always voted Labour since I was old enough to vote and I remained loyal through the years of disappointment in Labour leaders espousing right wing virtues, when the lefts chance finally came, we were never shown the same loyalty we had given through the Thatcher years or the Blair years, we were plotted against, smeared and ridiculed as cultists and the right of the party stood and watched, then joined in and party unity disappeared.
Why should myself and other on the left who showed so much loyalty through all those years only to be shown disloyalty when our chance came have any respect at all from a person on the right of the party trying the same old tricks that we have seen before. They want our votes, they don't want our voices. What sort of democracy is that, when all you are thought of is as votes and especially when votes will be used to push policies that are not Socialist.